Copper Metal Line Thermal Sensor IC Eliminates Charge Pump
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Solution Overview
Problem
Conventional thermal sensors rely on bipolar junction transistors (BJTs) for temperature sensing, which require a charge pump circuit due to decreased supply voltage, increasing chip area and inefficiency.
Innovation Solution
A thermal sensor IC utilizing a copper-made metal line as a thermistor, eliminating the need for BJT by varying resistance with temperature, and employing a converting circuit to generate a voltage signal for temperature determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a BJT is used for temperature sensing, then temperature sensing function is achieved, but chip area is greatly increased due to the required charge pump circuit
Solution Approach 1:
The patent extracts and eliminates the charge pump circuit from the thermal sensor system by replacing the BJT-based temperature sensing mechanism with a metal line resistance-based mechanism. This removal of the charge pump circuit directly reduces the chip area while maintaining the temperature sensing function through the resistance-temperature relationship of the metal line.
Solution Approach 2:
The patent changes the fundamental sensing parameter from BJT electrical characteristics (requiring charge pumping) to metal line resistance characteristics. By utilizing the temperature-dependent resistance property of metal lines and implementing it through standard CMOS metal layers, the system achieves temperature sensing without requiring the charge pump circuit, thus reducing chip area.
2Reliability
If a BJT is used for temperature sensing, then temperature sensing is achieved, but device complexity increases due to the charge pump circuit
Solution Approach 1:
The patent removes the charge pump circuit from the system by extracting the temperature sensing function and implementing it through the inherent resistance-temperature relationship of metal lines. This elimination of the charge pump circuit directly reduces device complexity while preserving the temperature sensing capability.
Solution Approach 2:
The metal line itself serves as the temperature sensor by utilizing its intrinsic resistance-temperature relationship. The metal line's resistance naturally varies with temperature, providing the sensing function without requiring external charge pumping or additional active components, thereby simplifying the overall device architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces chip area by eliminating BJT and charge pump circuit, while utilizing copper's high temperature coefficient for improved linearity and effective temperature sensing.
Implementation Method 1
a resistance of the resistor is varied with a temperature of the resistor
Data Source
AI summary
The present invention provides a thermal sensor integrated IC having a resistor and a converting circuit. The resistor is implemented by at least one metal line, wherein a resistance of the resistor is varied with a temperature of the resistor, the resistor has a first terminal and a second terminal, and one of the first terminal and the second terminal is arranged to provide a voltage signal corresponding to the resistance. The converting circuit is coupled to the resistor, and is configured to convert the voltage signal to an output signal for determining the temperature. In one embodiment, the at least one metal line is made by copper.